1. Field of the Invention
The invention relates to a method for image processing, particularly to a processing method for image tracking.
2. Description of the Prior Art
In a monitoring environment, particularly in the indoor place, when light is switched on or switched off, the lamplight of monitoring environment will be changed suddenly and greatly. It may cause the wrong color information of background image in the monitoring system designed by referring the background information. It will be unable to cut out the correct object from the background. Thus, in order to adapt to lightness variation, it is necessary to calibrate the color of background image.
In the relevant U.S. Pat. No. 5,548,659, when the image is tracked, a lot of noise is mixed in the retrieved information of moving-object due to the lightness variation. Thus the patent adopts the noise model formula to deal with the problem of light source. As for the light processing method, the linear regression model is used to retrieve the sampling points in the picture. Correct the intensity of the original static light by comparing the light intensity of the moving-object and the light intensity of the original static image.
In the relevant Taiwan Patent No. 1220969, upon dealing with the lightness variation caused by weather, the system obtains the difference value by comparing the initial background with successive images. If the difference value is greater than the default threshold value of the system, the background will be updated. Otherwise, it will not be updated.
The above-mentioned inventions are more suitable for the condition that the lightness variation changes progressively, which are not proper that the lightness variation will changes suddenly, especially in the indoor environment, such as tunnel. If the background convergence method is adopted again, it will take longer time to obtain correct background information, and it is very inconvenient to use it practically. Thus, it is necessary to provide a new invention that can update the background information correctively and timely.